#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int getNumber(int n) {
	if (n < 2) return n;
	vector<int>dp(n + 1);
	dp[0] = 1;
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= i; ++j) {
			dp[i] += dp[i - j];
		}
	}
	return dp.back();
}

int main() {
	int n;
	cin >> n;
	cout << getNumber(n) << endl;
}